Re: [Qemu-devel] Re: qdev property bug?

[Sebastian Herbszt]

Anthony Liguori wrote:
> Sebastian Herbszt wrote:
> > Anthony Liguori wrote:
> > > Michael S. Tsirkin wrote:
> > > > Further, we should error out when device is added.
> > > > Doing this during boot is way too late, management
> > > > won't be able to understand such errors and
> > > > won't be able to recover.
> > > >   
> > >
> > > I don't quite understand this.
> > >
> > > In 0.11, we never loaded option roms unless a user specified -boot 
> > > n.  If a user specified -boot n and used more than one nic type, I'm 
> > > fairly certain it would error out during start up because it would 
> > > run out of option rom space.  Maybe it required three types of nics, 
> > > but the point still remains.
> >
> > I think it used to be possible to have two different nic types and 
> > only load
> > one rom, e.g. -net nic,model=pcnet -net nic,model=e1000 -option-rom 
> > e1000.rom
> > Then use the boot menu to select the e1000 nic.
>
> That's a super hack :-)  The fact that works is pure luck.

Super hack? Maybe. Pure luck - no. Even if, it's still a regression if that's no
longer possible.

> > > In 0.12, we always load the option rom for a PCI device.  An easy 
> > > solution here would be to just gracefully handle the case where we 
> > > ran out of option rom space and (silently) stop loading additional 
> > > roms.  With respect to -boot n, it makes the behavior buggy (you 
> > > cannot boot from the second nic) but my original point is that that 
> > > is not a regression from 0.11.
> >
> > Even if i repeat myself [1] i suggest putting an option-rom loading 
> > flag to the -net option:
> > -net nic,model=e1000,rom=[on,off,e1000.bin]
>
> Well it ought to be a qdev property and it ought to be applicable to 
> every PCI device.

And ISA too.

> > > For 0.13, we should probably allow a user to suppress option rom 
> > > loading for a given PCI device.  The limited space is a pretty good 
> > > justification for that.
> >
> > The default behaviour should be not loading option-roms; users should 
> > request those.
>
> I disagree.  A user should not have to decide whether they want PXE boot 
> or not when they create a VM.  The less decisions a user has to make up 
> front the easier qemu is to use.

If i want PXE boot on my computer, i have to enter the BIOS and enable it.
If qemu starts to automagically enable stuff people might want to use, some
people will end up with long command lines just to disable it again.

- Sebastian